Soricidin (NCBI accession no. POC2C6) is a fifty-four amino acid paralytic peptide isolated from the submaxilary saliva gland of the Northern Short-tailed Shrew (Blarina brevicauda). U.S. Pat. No. 7,119,168 (incorporated by reference herein in its entirety) describes soricidin, its paralytic activity and usefulness of the peptide for conditions, such as treating pain and neuromuscular disease. U.S. Pat. No. 7,273,850 (incorporated by reference herein in its entirety) describes that soricidin has paralytic activity, and among other things, provides data that it inhibits calcium uptake in two ovarian cancer cell lines.
One group of calcium ion channels implicated in cancer is the Transient Receptor Potential (TRP) channels that are found across the invertebrates and vertebrates. The Transient Receptor Potential Vanilloid (TRPV) members of the TRP super-family were named after it was discovered that they activate in the presence of vanilloids (capsaicin from hot peppers for example). The first four of these receptors tested (TRPV1, TRPV2, TRPV3 and TRPV4) all responded to capsaicin and were also responsible for detecting changes in temperature and other environmental signals. The remaining two of the TRPV sub-family, TRPV5 and TRPV6, were found predominantly in epithelial type or derived tissues and were responsible for influx of calcium ion into the cell. U.S. Pat. No. 7,205,108 describes genes encoding TRPV 8, 9 and 10 and their use as biomarkers for cancer and in associated diagnostic and therapeutic methods.
TRPV6 was identified as responsible for import of calcium into epithelial tissues of the intestine and hence uptake of calcium from the diet. These channels were also shown to be present in a number of other tissues in varying amounts, but most notably intestinal epithelial cell, kidney, placenta and pancreas. The expression of TRPV6 was measured as highly elevated in some cancer tissues and in some known ovarian, breast, prostate, and leukemia cancer cell-lines. (Peng et al. 2000; Zhuang et al. 2002).
Accordingly, there is a need for compounds and associated methods for detecting cells that express TRPV6. There is also a need for compositions and methods capable of targeting cells that express TRPV6 for the delivery of agents useful for the diagnosis or treatment of cancer.